When a composite powder in which two or more powders are combined is manufactured as a composite of organic powder and inorganic powder, a method for manufacturing a composite powder, which includes preparing underlying powder particles (A) and coating surfaces of the powder particles (A) with other powder particles (B), has been generally used. However, such technology has a drawback in that it has a complicated procedure due to a two-step manufacturing process, and also unique characteristics of the two or more powders may not be suitably exhibited. On the other hand, the method differs in that, when a spray drying process and an electro-spraying process are applied to a powdering method to manufacture a composite powder, a granular powder may be manufactured using a one-step process by uniformly dispersing the other powder particles (B) in the underlying powder particles (A) so that the other powder particles (B) permeate into the underlying powder particles (A).
Spray drying technology is a method that includes spraying a material in a dissolved state, which is composed of a raw material powder, a solvent, and a binder, using a spraying unit such as a nozzle or a rolling disk and instantly drying the dissolved material with hot wind. More specifically, the spray drying is a technique in which a granular product is directly obtained from a liquid raw material by atomizing a liquid raw material such as a solution, an emulsion, a dispersion, a suspension, a slurry, or the like to increase a surface area of the liquid raw material so as to increase a heat-receiving area, and instantly drying the liquid raw material through direct contact with a hot air current, and is characterized in that the drying and powdering are performed in a single step.
Therefore, because the contact of the products with heat is realized within several seconds, the spray drying has advantages in that it has a relatively small effect on physical properties of the products and the produced products may be easily handled. Therefore, the spray drying has been widely used to dry a natural extract and obtain granules when fine ceramics, milk powders, medicines, foods, dyes, and pigments are manufactured.
Korean Unexamined Patent Publication No. 2002-0091779 discloses a spray drying process, which includes spraying slurry including a raw material powder to form droplets and drying the droplets to obtain ceramic granules, thereby manufacturing a ceramic powder having excellent dispersing and filling properties. Korean Unexamined Patent Publication No. 2014-0110439 discloses a method for manufacturing a spherical boron nitride powder having a constant particle size using a spray drying technique.
Meanwhile, electro-spraying technology is a method for manufacturing fine particles, which includes injecting a polymer solution having certain electrical conductivity and viscosity through a capillary tube and applying an electrostatic force to the polymer solution. Generally, when the polymer solution is sprayed through a nozzle disposed in a vertical position, the balance between the gravity and the surface tension of the polymer solution is made at an end of the nozzle to form hemispherical drops so that the drops hang from the end of the nozzle. In this case, when an electric field is applied to the hemispherical drops, an orientation of charges or dipoles on surfaces of the hemispherical drops is induced at the interface between an air space and the solution, and a force opposing the surface tension is generated due to the repulsive power of such charges or dipoles. Therefore, a hemispherical surface of the end of the nozzle is stretched to form a conical surface referred to as a Taylor cone, and a charged polymer solution is released from the Taylor cone when the repulsive power of the charges or dipoles is greater than a force overcoming the surface tension. In this case, the polymer solution having low viscosity is sprayed in the form of fine drops due to the surface tension. Like the spray drying, the electro-spraying includes powdering the polymer solution in a single step.
The electro-spraying has advantages in that particles may be easily prepared due to a simple shape and structure of the device, the prepared particles may have a mono-dispersed distribution, and the electro-spraying is useful in manufacturing particles having various sizes ranging from several tens of nanometers to several hundreds of micrometers. Therefore, the electro-spraying has been widely used in the fields of thin film attachment, coating of a metal surface, mass and structural analyses of proteins and biochemical materials, and the like.
In recent years, research has been conducted to apply the electro-spraying to generation of particles including a drug in the field of drug delivery. For example, Registered Korean Patent No. 10-1471280 discloses a method for manufacturing ultrafine nanopowders of a poorly soluble substance, which includes electro-spraying a poorly soluble substance solution, which is prepared by dissolving a poorly soluble substance in an organic solvent and dispersing a surfactant in the resulting solution, in order to improve an in vivo absorption rate of the poorly soluble drug.
Considering that the spray drying and electro-spraying techniques may be useful in preparing a liquid raw material into granules through a one-step process, easily adjusting a particle size of the granules, and manufacturing spherical particles, the present inventors have developed a method of uniformly impregnating amorphous coarse jade powder particles in a porous polymer using spray drying and electro-spraying processes. Therefore, the present invention has been completed based on the facts.